Aqueous dispersion and the use thereof in the production of coating agents, adhesives and sealing agents that can be cured by heat or by actinic radiation

ABSTRACT

Novel aqueous dispersion comprising at least one polymer containing on average (i) at least one primary and/or secondary carbamate group, (ii) at least one functional group having at least one bond which may be activated with actinic radiation, and (iii) at least one dispersive ionic functional group; process for preparing it and its use for preparing coating materials, adhesives and sealing compounds which are curable thermally and with actinic radiation, and also novel coating materials, adhesives and sealing compounds consisting of or comprising the novel aqueous dispersion.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Phase Application of Patent ApplicationPCT/EP01/09699 filed on 22 Aug. 2001, which claims priority to DE 100 41634.9, filed on 24 Aug. 2000.

The present invention relates to a novel aqueous dispersion. The presentinvention further relates to a novel process for preparing aqueousdispersions. The present invention additionally relates to the use ofthe novel aqueous dispersions to prepare coating materials, adhesives,and sealing compounds which are curable thermally and with actinicradiation. The present invention relates not least to novel coatingmaterials, adhesives, and sealing compounds which are curable thermallyand with actinic radiation. Moreover, the present invention relates tothe use of the novel coating materials, adhesives, and sealing compoundswhich are curable thermally and with actinic radiation to produce novelcoatings, adhesive films, and seals.

Automobile manufacturers and their customers are subjecting automotiveOEM finishes and refinishes to increasing requirements in terms ofcorrosion resistance, mechanical stability—resistance to scratching bywash brushes, for example—stonechip resistance, and the overall visualimpression, including the optical effects. As is known, theserequirements are met to a certain extent by a multicoat systemcomprising, above one another on a metal bodywork panel, anelectrodeposition coat, a surfacer coat or antistonechip primer coat,and a multicoat color and/or effect system comprising a color and/oreffect basecoat and at least one clearcoat.

In addition, however, the coatings are also required to meet theenvironmental requirements, which have risen continuously in recentyears, such as the reduction in the amount of organic solvents, orcomplete absence of solvent.

In the course of these developments, aqueous coating materials havegradually been able to establish themselves. For instance, theelectrodeposition coating materials have for a long time already beenvirtually free from volatile organic constituents, especially organicsolvents. Likewise, aqueous coating materials based on polyurethanes areavailable which are used to produce surfacer coatings or antistonechipprimer coats (cf. Patents DE 40 05 961 A1 and EP 0 548 873 A1).

The use of aqueous basecoats as well, as described for example in PatentDE 197 22 862 C1, has made significant progress and has persistentlyreduced the emissions of volatile organic constituents.

Also available now are solvent-free or substantially solvent-freeclearcoats such as aqueous two-component (2K) or multi-component (3K,4K) clearcoats, powder clearcoats, powder slurry clearcoats, or liquid,solvent-free clearcoats curable with actinic radiation (100% systems).

The actinic radiation may comprise electromagnetic radiation such asvisible light, UV light or X-rays, or corpuscular radiation such aselectron beams.

Aqueous two-component (2K) or multi-component (3K, 4K) clearcoats aredisclosed, for example, in German Patent DE 44 21 823 A1. The essentialconstituents of two-component (2K) or multi-component (3K, 4K)clearcoats are known to be hydroxyl-containing binders andpolyisocyanate crosslinking agents, which must be stored separatelyprior to their use.

Powder clearcoats are known, for example, from German Patent DE 42 22194 A1 and the BASF Lacke+Farben AG product information leaflet“Pulverlacke” [powder coatings], 1990. The familiar essentialconstituents of powder clearcoats are binders containing epoxide groupsand crosslinking agents comprising polycarboxylic acids.

Powder slurry clearcoats are known, for example, from U.S. Pat. No.4,268,542 A, International Patent Application WO 96/32452 and GermanPatent Applications DE 195 18 392 A1 and DE 196 13 547 A1, and aredescribed in German Patent Application DE 198 14 471.7, unpublished atthe priority date of the present specification. Powder slurry clearcoatscomprise, as is known, powder clearcoats in dispersion in an aqueousmedium.

Clearcoats curable with actinic radiation are disclosed, for example, inPatents EP 0 540 884 A1, EP 0 568 967 A1, and U.S. Pat. No. 4,675,234 A.Their familiar constituents are compounds of low molecular mass,oligomeric compounds and/or polymeric compounds which are curable withactinic light and/or electron beams, preferably radiation-curablebinders, based in particular on ethylenically unsaturated prepolymersand/or ethylenically unsaturated oligomers; if desired, one or morereactive diluents; and, if desired, one or more photoinitiators.Examples of suitable radiation-curable binders are(meth)acryloyl-functional (meth)acrylate copolymers, polyetheracrylates, polyester acrylates, unsaturated polyesters, epoxy acrylates,urethane acrylates, amino acrylates, melamine acrylates, siliconeacrylates, and the corresponding methacrylates. It is preferred to usebinders that are free from aromatic structural units.

European Patent Application EP 0 928 800 A1 discloses a dual-curecoating material—curable thermally and with actinic radiation—comprisinga urethane (meth)acrylate containing free isocyanate groups and(meth)acryloyl groups, a photoinitiator, and an isocyanate-reactivecompound, especially a polyol or polyamine. This dual-cure coatingmaterial affords the opportunity to vary the profile of properties ofcoating material and coating and to tailor it to different end uses.

The disadvantage of the known dual-cure coating materials is that theyare two-component systems, where the constituents containing freeisocyanate groups must be stored separately from the constituentscontaining isocyanate reactive groups in the absence of water until thetime of their application, in order to prevent premature crosslinking.This, however, requires a high level of technical and planning effortfor storage, preparation, and application.

In the context of the production of multicoat color and/or effectsystems, the known aqueous basecoats and clearcoats are processedpreferably by the so-called wet-on-wet technique. In the wet-on-wettechnique, as is known, a basecoat material is applied to a primed orunprimed substrate, after which the resultant basecoat film is dried,overcoated with a clearcoat material, and the resultant clearcoat filmis cured together with the basecoat film, so giving the multicoat systemcomprising color and/or effect basecoat and protective clearcoat.

In the context of the wet-on-wet technique, the individual types ofclearcoat have specific strengths and weaknesses.

The aqueous clearcoats, for instance, may penetrate the dried aqueousbasecoat film during or after their application. Powder clearcoats maynot flow out sufficiently during curing, leading to structured surfaces.

After they have cured, clearcoats based on two-component (2K) ormulti-component (3K, 4K) clearcoat materials are stable to weatheringbut often not sufficiently abrasion-resistant. Clearcoats curable withactinic radiation often exhibit severe shrinkage in the course of theircuring, leading to delamination as a result of internal stresses.Furthermore, following their application to substrates of relativelycomplex shape, they may be cured inadequately in the shadow regions.Powder slurry clearcoats are more or less incompatible with somefrequently used aqueous basecoats, which may lead to cracking (mudcracking) in the multicoat system and to delamination of the coats.

German Patent Application DE 196 45 761 A1 discloses hydrophilicself-crosslinking polyurethanes containing olefinically unsaturatedgroups and terminal blocked isocyanate groups. The blocking agentstherein, however, are not specified in detail. These known hydrophilicself-crosslinking polyurethanes are used to prepare graft copolymers bythe emulsion polymerization method. The resultant dispersions of thegraft copolymers are used to prepare aqueous basecoats, and notclearcoats. The production of multicoat color and/or effect systems bythe wet-on-wet technique, in which basecoat films are overcoated withclearcoat films and then the two films are cured together, is notaddressed in the patent application. Nor is there any description in thepatent application of the combination of thermal curing and curing withactinic radiation (dual cure).

German Patent DE 197 22 862 C1 discloses an externally crosslinkinggraft copolymer obtainable by polymerizing olefinically unsaturatedmonomers in a dispersion of an olefinically unsaturated polyurethanecontaining hydrophilic functional groups and containing on average permolecule from 0.05 to 1.1 polymerizable pendent and/or terminal doublebonds. The known externally crosslinking graft copolymers of DE 197 22862 C1 are in the form of primary dispersions and are highly suitablefor preparing aqueous externally crosslinking coating materials,especially aqueous basecoats. They may comprise blocked isocyanates ascrosslinking agents. The externally crosslinking aqueous basecoats maybe used with advantage to produce multicoat color and/or effect systemsby the wet-on-wet technique. The patent, however, does not describe theuse of the primary dispersions to prepare clearcoats which can be curedthermally and with actinic radiation.

In the context of the present invention, the term “self-crosslinking”refers to the capacity of a binder (regarding the term, cf. RömppLexikon Lacke und Druckfarben, Georg Thieme Verlag, Stuttgart, N.Y.,1998, “Binders”, pages 73 and 74) to undergo crosslinking reactions withitself. This requires that the binders already contain both kinds ofcomplementary reactive functional groups which are necessary forcrosslinking. “Externally crosslinking”, on the other hand, is the termused for those coating materials in which one kind of the complementaryreactive functional groups is present in the binder and the other kindin a curing or crosslinking agent. For further details, reference ismade to Römpp, op. cit., “Curing”, pages 274 to 276, especially bottompage 275.

German Patent Application DE 199 47 045.5, unpublished at the prioritydate of the present specification, describes a clearcoat which iscurable thermally and with actinic radiation and is based on an aqueousdispersion containing hydroxyl groups, blocked isocyanate groups andolefinically unsaturated groups, and dispersive ionic groups. The use ofthese clearcoats in the context of the wet-on-wet technique is notdescribed therein.

German Patent Application DE 199 58 726.4, unpublished at the prioritydate of this present specification, describes a powder slurry curablethermally and with actinic radiation and comprising at least one aqueousdispersion. The dispersion is prepared from aliphatic polyisocyanates,compounds containing isocyanate-reactive functional groups and bondswhich may be activated by actinic radiation, low molecular massaliphatic compounds containing isocyanate-reactive functional groups,compounds containing isocyanate-reactive functional groups anddispersive functional groups, neutralizing agents for the dispersivefunctional groups, and blocking agents for isocyanate groups and/orcompounds containing blocked isocyanate groups, the blocked isocyanategroups being introduced into the dispersion by way of the reaction ofthe blocking agents with isocyanato-containing polyurethane prepolymers.The use of carbamate groups is not described in this patent application.

German Patent Application DE 199 08 013.5, unpublished at the prioritydate of the present specification, describes a pseudoplastic powderslurry curable with actinic radiation and, possibly, thermally,comprising solid spherical particles with an average size of from 0.8 to20 μm and a maximum size of 30 μm, the powder clearcoat slurrycontaining from 0.05 to 1 meq/g of ion-forming dispersive groups,corresponding to an average acid number or amine number of from 3 to 56g KOH/g solids (MEQ acid or amine of from 0.05 to 1.0 meq/g solids),preferably up to 28 (MEQ acid or amine: 0.5), and in particular up to 17(MEQ acid or amine: 0.3), having a neutralizing agent content of from0.05 to 1 meq/g and a viscosity of (i) from 50 to 1000 mPas at a shearrate of 1000 s⁻¹, (ii) from 150 to 8000 mPas at a shear rate of 10 s⁻¹,and (iii) from 180 to 12,000 mPas at a shear rate of 1 s⁻¹. Furthermore,the powder clearcoat slurry may comprise binders containing reactivefunctional groups such as hydroxyl groups, for example, which are ableto undergo thermal crosslinking reactions with crosslinking agents suchas blocked isocyanates. The use of carbamate groups such as —O—C(O)—NH₂is not described in the patent application.

German Patent Application DE 199 08 018.6, unpublished at the prioritydate of the present specification, describes a dual-cure powderclearcoat slurry comprising constituents containing both groups (A)which may be activated with actinic radiation and complementary reactivefunctional groups (B) which undergo thermal crosslinking reactions.Carbamate groups such as —O—C(O)—NH₂ are not used as groups (B).

German Patent Application DE 199 61 926.3, unpublished at the prioritydate of the present specification, describes compositions curablethermally and with actinic radiation which may be used, inter alia, toprepare powder slurry coating materials. The compositions comprise aconstituent (A) preparable from a polyisocyanate, a compound containingat least one bond which may be activated with actinic radiation and anisocyanate-reactive functional group, and at least one compoundcontaining at least one carbamate group and an isocyanate-reactivefunctional group. The constituent (A) may contain hydrophilic groupssuch as poly(ethylene oxide) monoalkyl ethers. The use of potentiallyanionic functional groups as dispersive groups and of neutralizing agentfor said groups is not described in the patent application. Furthermore,the constituents (A) contain no isocyanate-reactive functional groupssuch as hydroxyl groups.

German Patent Application DE 100 27 292.4, unpublished at the prioritydate of the present specification, describes dual-cure powder slurryclearcoats comprising numerous different polymers as binders, includingpolyurethanes. The binders may contain numerous different complementaryreactive functional groups which undergo thermal crosslinking reactions,these groups including isocyanate-reactive functional groups andcarbamate groups —O—C(O)—NH₂. As crosslinking agents, amino resins maybe used. No details are given regarding the preparation of an aqueousdispersion of a polyurethane containing functional groups which may beactivated with actinic radiation, isocyanate-reactive functional groups,dispersive functional groups such as carboxyl groups and carbamategroups. Where carboxyl groups are employed in the context of the patentapplication, they are used for thermal crosslinking with epoxide groupsas complementary reactive functional groups.

It is an object of the present invention to find a new aqueousdispersion which permits the preparation of new coating materialscurable thermally and with actinic radiation. In particular, the coatingmaterials should be suitable for use as powder slurry clearcoats.

Furthermore, the new aqueous dispersion should also be suitable for thepreparation of adhesives and sealing compounds.

The coating materials, adhesives and sealing compounds based on the newaqueous dispersions should give coatings, adhesives [sic], and sealswhich exhibit excellent weathering stability, chemical resistance,hardness, flexibility, and scratch resistance and which do not tendtoward yellowing.

It is a further object of the present invention to find a new processfor preparing aqueous dispersions.

It is yet another object of the present invention to provide a newprocess for producing multicoat color and/or effect systems, saidprocess being devoid of the disadvantages of the prior art and insteadproviding, safely and reliably, multicoat systems which are of theutmost optical quality as regards color, effect, gloss and DOI(distinctness of the reflected image), have a smooth, unstructured,hard, flexible, and scratch-resistant surface, are weathering-stable,chemical-resistant and etch-resistant, do not yellow, and show nocracking or delamination of the coats.

Accordingly, we have found the novel aqueous dispersion comprising atleast one polymer containing on average

-   (i) at least one primary and/or secondary carbamate group,-   (ii) at least one functional group having at least one bond which    may be activated with actinic radiation, and-   (iii) at least one dispersive ionic functional group, referred to    below as the “dispersion of the invention”.

We have also found the novel coating materials, adhesives, and sealingcompounds which comprise the dispersions of the invention and/or thepolyurethane dispersions obtained by means of the preparation process ofthe invention, referred to below as the “coating materials, adhesives,and sealing compounds of the invention”.

Further subject matter of the invention will emerge from thedescription.

In the light of the prior art it was surprising and unforeseeable forthe skilled worker that the object on which the present invention wasbased might be achieved by means of the dispersion of the invention. Aparticular surprise was that the dispersion of the invention possessedsuch extremely broad applicability and permitted the preparation ofcoating materials, adhesives, and sealing compounds which even onsubstrates of complex shape could be cured completely to give coatings,adhesive films, and seals which were highly scratch-resistant andchemical-resistant and did not tend toward yellowing. It should behighlighted in particular that by means of the dispersion of theinvention it was possible to produce multicoat systems exclusively onthe basis of aqueous coating materials.

The dispersion of the invention comprises at least one polymer.

The amount of the polymer in the dispersion of the invention may varyvery widely. It is preferably from 10 to 70, more preferably from 12 to68, with particular preference from 13 to 66, with very particularpreference from 14 to 64, and in particular from 15 to 62% by weight,based in each case on the dispersion of the invention.

The polymer contains on average at least one primary and/or secondarycarbamate group of the general formula I—O—C(O)—NHR  (I),where the variable R is a hydrogen atom or an organic radical. Examplesof suitable organic radicals are alkyl groups of 1 to 18 carbon atoms,cycloalkyl groups of 3 to 12 carbon atoms, aryl groups of 6 to 20 carbonatoms, and arylalkyl groups of 6 to 30 carbon atoms. Preferably, primarycarbamate groups are used.

In accordance with the invention it is of advantage if the polymercontains on average more than one, preferably more than two, withparticular preference more than three, with very particular preferencemore than four, and in particular more than five carbamate groups of thegeneral formula I.

The polymer contains on average at least one functional group having atleast one bond which may be activated with actinic radiation.

In the context of the present invention, actinic radiation iselectromagnetic radiation such as near infrared (NIR), visible light, UVradiation or X-rays, especially UV radiation, or corpuscular radiationsuch as electron beams.

A bond which may be activated with actinic radiation is a bond which onexposure to actinic radiation becomes reactive and, with other activatedbonds of its kind, undergoes polymerization reactions and/orcrosslinking reactions which proceed in accordance with free-radicaland/or ionic mechanisms. Examples of suitable bonds are carbon-hydrogensingle bonds and carbon-carbon, carbon-oxygen, carbon-nitrogen,carbon-phosphorus, and carbon-silicon single or double bonds. Of these,the carbon-carbon double bonds are particularly advantageous and aretherefore used with very particular preference in accordance with theinvention. For brevity, they are referred to below as “double bonds”.

Particularly suitable double bonds are present, for example, in(meth)acrylate, ethacrylate, crotonate, cinnamate, vinyl ether, vinylester, dicyclopentadienyl, norbornenyl, isoprenyl, isopropenyl, allyl,and butenyl groups; dicyclopentadienyl ether, norbornenyl ether,isoprenyl ether, isopropenyl ether, allyl ether, and butenyl ethergroups; and dicyclopentadienyl ester, norbornenyl ester, isoprenylester, isopropenyl ester, allyl ester, and butenyl ester groups. Ofthese, the acrylate groups offer very particular advantages, and so areused with very particular preference in accordance with the invention.

In accordance with the invention it is of advantage if the polymercontains on average more than one, preferably more than two, withparticular preference more than three, with very particular preferencemore than four, and in particular more than five of the above-describedfunctional groups that may be activated with actinic radiation.

The polymer contains on average at least one dispersive (potentially)ionic functional group. Examples of suitable (potentially) cationicgroups are amino groups. Examples of suitable (potentially) anionicgroups are carboxylic acid, sulfonic acid, and phosphonic acid groups,especially carboxylic acid groups. In the dispersion for use inaccordance with the invention they are present in an amount such as togive, based on the solids of the dispersion of the invention, an acidnumber or amine number of from 3.0 to 100, preferably from 4.0 to 90,more preferably from 5.0 to 80, with particular preference from 6.0 to70, with very particular preference from 6.0 to 60, and in particularfrom 6 to 50 mg KOH/g. In this context, dispersive (potentially) anionicfunctional groups are of advantage.

The polymer may contain on average at least one isocyanate-reactivefunctional group. Examples of suitable isocyanate-reactive functionalgroups are thiol, hydroxyl and/or primary and/or secondary amino groups,especially hydroxyl groups. It may of advantage if the polymer containson average more than one, preferably more than two, with particularpreference more than three, with very particular preference more thanfour, and in particular more than five isocyanate-reactive functionalgroups.

Examples of suitable polymers are random, alternating and/or block,linear and/or branched and/or comb (co)polymers of ethylenicallyunsaturated monomers, and polyaddition resins and/or polycondensationresins. Regarding these terms, reference is made to Römpp, op. cit.,page 457, “Polyaddition” and “Polyaddition resins (polyadducts)”, andpages 463 and 464, “Polycondensates”, “Polycondensation”, and“Polycondensation resins”.

Examples of highly suitable polymers are linear and/or branched and/orblock, comb and/or random poly(meth)acrylates or acrylate copolymers,polyesters, alkyds, polyurethanes, acrylated polyurethanes, acrylatedpolyesters, polylactones, polycarbonates, polyethers, epoxy resin-amineadducts, (meth)acrylatediols, partially hydrolyzed polyvinyl esters, andpolyureas, but especially polyurethanes.

The polymers are prepared by means of conventional methods fromappropriate starting compounds containing (i) primary and/or secondarycarbamate groups and/or groups convertible to carbamate groups, (ii)functional groups having at least one bond which may be activated withactinic radiation, and/or (iii) dispersive (potentially) ionicfunctional groups, and, if desired, (iv) isocyanate-reactive functionalgroups. Alternatively, the groups in question may be introduced into theparent structures of the polymers by means of polymer-analogousreactions. In that case the resultant polymers are dispersed in water orin an aqueous medium (secondary dispersion), where they have not beenprepared in water or in an aqueous medium (primary dispersion).

Particularly advantageous dispersions of the invention are polyurethanedispersions.

Especially advantageous dispersions of the invention comprise at leastone polyurethane preparable by reacting, in a procedure in accordancewith the invention,

-   (A) at least one aliphatic polyisocyanate having an isocyanate    functionality of from 2.0 to 6.0 with-   (B) at least one compound containing at least one    isocyanate-reactive functional group and at least one bond that may    be activated with actinic radiation,-   (C) at least one low molecular mass aliphatic compound containing at    least two isocyanate-reactive functional groups,-   (D) at least one compound containing at least one    isocyanate-reactive functional group and at least one dispersive    (potentially) ionic, especially anionic, functional group,-   (E) at least one neutralizing agent for the dispersive functional    groups of the compound (D), and-   (F) at least one compound containing at least one primary and/or    secondary carbamate group and/or at least one functional group which    may be converted into a carbamate group, and at least one    isocyanate-reactive group, and also, if desired,-   (G) at least one compound containing an isocyanate-reactive    functional group, other than the compounds (B) to (F).

The aliphatic—including cycloaliphatic—polyisocyanate (A) has anisocyanate functionality of from 2.0 to 6.0, preferably from 2.0 to 5.0,more preferably from 2.0 to 4.5, and in particular from 2.0 to 3.5. Inthe context of the present invention, the term “cycloaliphaticdiisocyanate” refers to a diisocyanate in which at least one isocyanategroup is attached to a cycloaliphatic radical.

Examples of suitable cycloaliphatic polyisocyanates (A) having anisocyanate functionality of 2.0 are isophorone diisocyanate (i.e.,5-isocyanato-1-isocyanatomethyl-1,3,3-trimethylcyclohexane),5-isocyanato-1-(2-isocyanatoeth-1-yl)-1,3,3-trimethylcyclohexane,5-isocyanato-1-(3-isocyanatoprop-1-yl)-1,3,3-trimethylcyclohexane,5-isocyanato-(4-isocyanatobut-1-yl)-1,3,3-trimethylcyclohexane,1-isocyanato-2-(3-isocyanatoprop-1-yl)cyclohexane,1-isocyanato-2-(3-isocyanatoeth-1-yl)cyclohexane,1-isocyanato-2-(4-isocyanatobut-1-yl)cyclohexane,1,2-diisocyanatocyclobutane, 1,3-diisocyanatocyclobutane,1,2-diisocyanatocyclopentane, 1,3-diisocyanatocyclopentane,1,2-diisocyanatocyclohexane, 1,3-diisocyanatocyclohexane,1,4-diisocyanatocyclohexane, dicyclohexylmethane 2,4′-diisocyanate ordicyclohexylmethane 4,4,′-diisocyanate, especially isophoronediisocyanate.

Examples of suitable acyclic aliphatic diisocyanates for use inaccordance with the invention are trimethylene diisocyanate,tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylenediisocyanate, ethylethylene diisocyanate, trimethylhexane diisocyanate,heptanemethylene [sic] diisocyanate, and diisocyanates derived fromdimeric fatty acids, as marketed under the commercial designation DDI1410 by the Company Henkel and described in Patents WO 97/49745 and WO97/49747, especially2-heptyl-3,4-bis(9-isocyanatononyl)-1-pentycyclohexane, or 1,2-, 1,4- or1,3-bis(isocyanatomethyl)cyclohexane, 1,2-, 1,4- or1,3-bis(2-isocyanatoeth-1-yl)cyclohexane,1,3-bis(3-isocyanatoprop-1-yl)cyclohexane or 1,2-, 1,4- or1,3-bis(4-isocyanatobut-1-yl)cyclohexane.

Of these, hexamethylene diisocyanate is of particular advantage and istherefore used with very particular preference in accordance with theinvention.

Examples of suitable polyisocyanates (A) having an isocyanatefunctionality >2 are polyisocyanates, especially those based onhexamethylene diisocyanate which contain isocyanurate, biuret,allophanate, iminooxadiazinedione, urethane, urea, carbodiimide and/oruretdione groups and are obtainable in conventional manner from theabove-described diisocyanates. Advantageous such polyisocyanates (A) arethose containing allophanate groups and/or isocyanurate groups,especially those based on hexamethylene diisocyanate, and so it is thesethat are used with particular preference in accordance with theinvention. Examples of suitable preparation processes andpolyisocyanates are known, for example, from Patents CA 2,163,591 A,U.S. Pat. No. 4,419,513 A, U.S. Pat. No. 4,454,317 A, EP 0 646 608 A1,U.S. Pat. No. 4,801,675 A, EP 0 183 976 A1, DE 40 15 155 A1, EP 0 303150 A1, EP 0 496 208 A1, EP 0 524 500 A1, EP 0 566 037 A1, U.S. Pat. No.5,258,482 A, U.S. Pat. No. 5,290,902 A, EP 0 649 806 A1, DE 42 29 183A1, and EP 0 531 820 A1.

Examples of suitable compounds (B) containing at least one, especiallyone, functional group and having per molecule at least one bond that maybe activated with actinic radiation are

-   -   allyl alcohol or 4-butyl vinyl ether;    -   hydroxyalkyl esters and hydroxycycloalkyl esters of acrylic acid        or methacrylic acid, especially of acrylic acid, obtainable by        esterifying aliphatic diols, examples being the above-described        low molecular mass diols (B) [sic], with acrylic acid or        methacrylic acid, or by reacting acrylic acid or methacrylic        acid with an alkylene oxide, especially hydroxyalkyl esters of        acrylic acid or methacrylic acid in which the hydroxyalkyl group        contains up to 20 carbon atoms, such as 2-hydroxyethyl,        2-hydroxypropyl, 3-hydroxypropyl, 3-hydroxybutyl,        4-hydroxybutyl, bis(hydroxymethyl)cyclohexane acrylate or        methacrylate; of these, 2-hydroxyethyl acrylate and        4-hydroxybutyl acrylate are particularly advantageous and are        therefore used with particular preference in accordance with the        invention; and    -   reaction products of cyclic esters, such as        epsilon-caprolactone, for example, and these hydroxyalkyl or        hydroxycycloalkyl esters.

Examples of suitable low molecular mass aliphatic compounds (C)containing at least two, especially two, isocyanate-reactive functionalgroups are polyols, especially diols, polyamines, especially diamines,and amino alcohols. Normally, the polyols and/or polyamines are usedalongside the diols and/or diamines in minor amounts in order tointroduce branching points into the polyurethanes. In the context of thepresent invention, minor amounts are amounts which do not cause gellingof the polyurethanes during their preparation. This applies mutatismutandis to the amino-alcohols.

Examples of suitable diols (C) are ethylene glycol, 1,2- or1,3-propanediol, 1,2-, 1,3- or 1,4-butanediol, 1,2-, 1,3-, 1,4- or1,5-pentanediol, 1,2-, 1,3-, 1,4-, 1,5- or 1,6-hexanediol, neopentylhydroxypivalate, neopentyl glycol, diethylene glycol, 1,2-, 1,3- or1,4-cyclohexanediol, 1,2-, 1,3- or 1,4-cyclohexanedimethanol,trimethylpentanediol, ethyl-butylpropanediol, the positionally isomericdiethyloctanediols, 2-butyl-2-ethyl-1,3-propanediol,2-butyl-2-methyl-1,3-propanediol, 2-phenyl-2-methyl-1,3-propanediol,2-propyl-2-ethyl-1,3-propanediol, 2-di-tert-butyl-1,3-propanediol,2-butyl-2-propyl-1,3-propanediol,1-dihydroxymethylbicyclo[2.2.1]heptane, 2,2-diethyl-1,3-propanediol,2,2-dipropyl-1,3-propanediol, 2-cyclohexyl-2-methyl-1,3-propanediol,2,5-dimethyl-2,5-hexanediol, 2,5-diethyl-2,5-hexanediol,2-ethyl-5-methyl-2,5-hexanediol, 2,4-dimethyl-2,4-pentanediol,2,3-dimethyl-2,3-butanediol, dihydroxymethylcyclohexane,bis(hydroxycyclohexyl)propane, tetramethylcyclobutanediol,cyclooctanediol or norbornanediol, especially 1,2-, 1,3- and/or1,4-cyclohexanedimethanol, which are referred to collectively below ascyclohexanedimethanol.

Examples of suitable polyols (C) are trimethylolethane,trimethylolpropane and glycerol, pentaerythritol or homopentaerythritoland sugar alcohols such as threitol or erythritol or pentitols such asarabitol, adinitol or xylitol or hexitols such as sorbitol, mannitol ordulcitol.

Examples of suitable diamines (C) are hydrazine, ethylenediamine,propylenediamine, 1,4-butylenediamine, piperazine, 1,4-cyclohexyldimethylamine, 1,6-hexamethylenediamine, trimethylhexamethylenediamine,methanediamine [sic], isophoronediamine, and4,4,′-diaminodicyclohexylmethane.

Examples of suitable polyamines (C) are diethylenetriamine,triethylenetetramine, dipropylenediamine, and dibutylenetriamine.

Examples of suitable amino alcohols (C) are ethanolamine,diethanolamine, and triethanolamine.

Of these compounds (C), cyclohexanedimethanol offers particularadvantages and is therefore used with preference in accordance with theinvention.

Examples of suitable compounds (D), containing at least oneisocyanate-reactive functional group and at least one dispersivefunctional group, in particular a (potentially) anionic group, aremercapto-, hydroxy-, amino- or iminocarboxylic, -phosphonic or -sulfonicacids, such as mercapto acetic acid (thio glycolic acid),mercaptopropionic acid, mercaptosuccinic acid, hydroxy acetic acid,hydroxydecanoic acid, hydroxydodecanoic acid, 12-hydroxystearic acid,hydroxyethanesulfonic acid, hydroxypropanesulfonic acid,mercaptoethanesulfonic acid, mercaptopropanesulfonic acid,aminopropanesulfonic acid, glycine, iminodiacetic acid,2,2-dimethylolacetic acid, 2,2-dimethylolpropionic acid,2,2-dimethylolbutyric acid, 2,2-dimethylolpentanoic acid,α,δ-diaminovaleric acid, 3,4-diaminobenzoic acid,2,4-diaminotoluenesulfonic acid, and 2,4-diaminodiphenyl ether sulfonicacid, especially hydroxyacetic acid. They are used in amounts such thatthe above-described acid numbers are obtained.

Examples of suitable neutralizing agents (E) for the potentially anionicgroups of the compound (D) are alkali metal and alkaline earth metalhydroxides, oxides, carbonates, and hydrogen carbonates, and alsoammonia and organic primary, secondary and/or tertiary amines, such asmonoethanolamine, diethanolamine, diethylamine, monoisopropanolamine,diisopropanolamine, morpholine, 2-amino-2-methyl-1-propanol,trimethylamine, triethylamine, tributylamine, dimethylaniline,diethylaniline, triphenylamine, dimethylethanolamine,diethylethanolamine, methyldiethanolamine, 2-aminomethylpropanol,dimethylisopropylamine, and/or dimethylisopropanolamine, for example.

Examples of suitable compounds (F) containing at least one, especiallyone, carbamate group and/or at least one, especially one, functionalgroup which may be converted into carbamate groups are hydroxyethylcarbamate or hydroxypropyl carbamate, especially hydroxypropylcarbamate. An example of a suitable functional group which may beconverted into a carbamate group is the cyclic ethylene carbonate group,which may be converted into a primary carbamate group using ammonia. Theethylene carbonate group itself may be prepared by reacting thepolyisocyanate, the polyacid or the polyepoxide with, for example,glycidol and then reacting the epoxide groups with carbon dioxide. Inthe case of the polyepoxides, care should be taken to ensure that at thetime of the reaction with carbon dioxide there are no longer any epoxidegroups attached to the parent structure.

Examples of suitable compounds (G), which are different from thecompounds (B) to (F) and contain an isocyanate-reactive functionalgroup, are alcohols or monoamines (C) such as ethanol, propanol,n-butanol, sec-butanol, tert-butanol, amyl alcohols, hexanols, fattyalcohols, phenol, allyl alcohol or ethylhexylamine. They are usedpreferably in conjunction with compounds (C) of higher functionality, inorder to prevent gelling of the polyurethanes during their preparation.

Via the amount of the dispersive ionic functional groups and theirdegree of neutralization, in particular, it is possible to control thepreparation of the polyurethane for use in accordance with the inventionin such a way that the aqueous dispersions run the whole gamut ofsalvation between molecularly disperse solution of the polyurethanes andstabilized powder slurry particles.

Preferably, these solid, finely divided particles have an average sizeof from 3.0 to 10 μm, in particular from 3.0 to 5 μm.

Viewed in terms of its method, the preparation of the polyurethanedispersion of the invention from the starting materials described abovehas no special features but instead takes place in accordance with thecustomary and known methods of preparing aqueous polyurethanedispersions, as described, for example, in the patents cited at theoutset that relate to aqueous basecoats.

In accordance with the invention it is of advantage to synthesize thepolyurethane of the invention by means of the preparation process of theinvention.

For example, in one preferred variant of the preparation process of theinvention, at least one compound (B) is reacted in a first process stepwith a molar excess of at least one compound (A) to give an adductcontaining free isocyanate groups and bonds that may be activated withactinic radiation. In a second process step, the adduct is reacted withat least one compound (D) and, if desired, (C) to give a prepolymercontaining isocyanate groups. In a further process step, at least oneneutralizing agent (E) and, if desired, at least one compound (C) areadded, to give a partially or fully neutralized prepolymer. In a fourthprocess step, the neutralized prepolymer is reacted with a compound (F).If any free isocyanate groups are still present, they are reactedpreferably with at least one compound (G) and/or (C), so giving thepolyurethane for use in accordance with the invention. In addition tothe compounds (G) and/or (C), it is possible to use the blocking agentsknown from U.S. Pat. No. 4,444,954 A. In one further variant of thepreparation process of the invention, the starting materials may bereacted with one another in a one-pot process.

The polyurethane of the invention is subsequently transferred to anaqueous medium, so giving the polyurethane dispersion of the invention.

The aqueous medium comprises essentially water. The aqueous medium mayinclude minor amounts of organic solvents, reactive diluents curablewith actinic radiation, photoinitiators, free-radical polymerizationinitiators, and/or other customary coatings additives and/or otherdissolved solid, liquid or gaseous, organic and/or inorganic, low and/orhigh molecular mass substances. In the context of the present invention,a “minor amount” is an amount which does not change the aqueous natureof the aqueous medium. However, the aqueous medium may also comprisewater alone.

The resultant dispersion of the invention may be self-crosslinking inthe sense referred to at the outset.

The dispersion of the invention is used to prepare the coatingmaterials, adhesives, and sealing compounds of the invention.

Particular advantages result if the polyurethane dispersion of theinvention is used to prepare the coating materials of the invention. Thecomment [sic] below, however, apply mutatis mutandis to the adhesivesand sealing compounds of the invention as well.

The coating materials of the invention may comprise pigmented orunpigmented coating materials. Examples of pigmented coating materialsare surfacers, aqueous basecoats, and solid-color topcoats. Examples ofunpigmented coating materials are clearcoats, especially powder slurryclearcoats.

The amount of the dispersion of the invention in the coating materialsof the invention may vary widely and is guided is guided [sic] inparticular by the end use, by the amount of polymers in the dispersionof the invention, and by the other constituents present, in particularby whether a crosslinking agent is used or not. The amount is preferablyfrom 10 to 100, more preferably from 20 to 99, with particularpreference from 30 to 99, with very particular preference from 40 to 99,and in particular from 50 to 99% by weight, based in each case on thetotal amount of the coating material.

Preferably, the coating materials of the invention include at least onecrosslinking agent containing on average per molecule at least onecarbamate-reactive functional group and, if desired, at least one of theabove-described bonds that may be activated with actinic radiation.

Examples of suitable carbamate-reactive functional groups are N-methylolgroups and N-methylol ether groups.

Preference is given to the use of amino resins. Examples of highlysuitable amino resins are melamine resins, guanamine resins, and urearesins. In this context it is possible to use any amino resin that issuitable for transparent topcoats or clearcoats, or a mixture of suchamino resins. For further details, reference is made to Römpp, op. cit.,page 29, “Amino resins”, the textbook “Lackadditive” [Coatingsadditives] by Johan Bieleman, Wiley-VCH, Weinheim, N.Y., 1998, pages 242et seq., and the book “Paints, coatings and solvents”, second,completely revised edition, eds. D. Stoye and W. Freitag, Wiley-VCH,Weinheim, N.Y., 1998, pages 80 ff. Also suitable are the customary andknown amino resins some of whose methylol and/or methoxymethyl groupshave been defunctionalized by means of carbamate or allophanate groups.Crosslinking agents of this kind are described in U.S. Pat. No.4,710,542 A and EP 0 245 700 B1 and in the article by B. Singh andcoworkers, “Carbamylmethylated melamines, novel crosslinkers for thecoatings industry” in Advanced Organic Coatings Science and TechnologySeries, 1991, Volume 13, pages 193 to 207.

The amount of the crosslinking agent in the coating material of theinvention may vary widely and is guided in particular by itsfunctionality, by the end use, and by the other constituents present.Preferably, the amount of crosslinking agent is from 0.1 to 90, morepreferably from 0.5 to 80, with particular preference from 0.8 to 70,with very particular preference from 1.0 to 60, and in particular from1.5 to 50% by weight, based in each case on the total amount of thecoating material.

The coating material of the invention may further comprise at least oneadditive.

The selection is guided in particular by the intended use of thedual-cure composition of the invention. Preferably, these additives arenot volatile under the processing and application conditions of thecoating material of the invention and are not broken down by water.

Where the coating material of the invention is used as a surfacer,topcoat or basecoat, its additives include color and/or effect pigmentsin conventional amounts. The pigments may comprise organic or inorganiccompounds and may be effect and/or color pigments. On the basis of thislarge number of suitable pigments, therefore, the dual-cure coatingmaterial of the invention assures a universal scope of application andpermits the realization of a large number of color shades and opticaleffects.

Effect pigments which may be used include metal flake pigments such asstandard commercial aluminum bronzes, aluminum bronzes chromated inaccordance with DE 36 36 183 A1, and standard commercial stainless steelbronzes, and also nonmetallic effect pigments, such as pearlescentpigments and interference pigments, for example. For further details,reference is made to Römpp, op. cit., pages [sic] 176, “Effect pigments”and pages 380 and 381, “Metal oxide-mica pigments” to “Metal pigments”.

Examples of suitable inorganic color pigments are titanium dioxide, ironoxide, Sicotrans yellow, and carbon black. Examples of suitable organiccolor pigments are thioindigo pigments, indanthrene blue, Cromophthalred, Irganzine orange, and Heliogen green. For further details,reference is made to Römpp, op. cit., pages 180 and 181, “Iron-bluepigments” to “Black iron oxide”, pages 451 to 453, “Pigments” to“Pigment volume concentration”, page 563, “Thioindigo pigments”, andpage 567, “Titanium dioxide pigments”.

Furthermore, the dual-cure coating material of the invention, especiallyas a surfacer, may comprise organic and inorganic fillers inconventional, effective amounts. Examples of suitable fillers are chalk,calcium sulfate, barium sulfate, silicates such as talc or kaolin,silicas, oxides such as aluminum hydroxide or magnesium hydroxide, andorganic fillers such as textile fibers, cellulose fibers, polyethylenefibers or wood flour. For further details, reference is made to Römpp,op. cit., pages 250 ff., “Fillers”.

These pigments and fillers may also be incorporated into the dual-curecoating materials of the invention by way of pigment pastes.

The above-described pigments and fillers are omitted if the coatingmaterials of the invention are used in their especially preferredutility as clearcoats.

Examples of suitable additives which may be present in the clearcoats,surfacers, basecoats, and topcoats of the invention are

-   -   customary and known oligomeric and polymeric binders such as        thermally curable, linear and/or branched and/or block, comb        and/or random poly(methyl)acrylates or acrylate copolymers,        polyesters, alkyds, polyurethanes, acrylated polyurethanes,        acrylated polyesters, polylactones, polycarbonates, polyethers,        epoxy resin-amine adducts, (meth)acrylatediols, partially        hydrolyzed polyvinyl esters, or polyureas;    -   customary and known reactive diluents curable thermally and/or        with actinic radiation, such as positionally isomeric        diethyloctanediols or hydroxyl-containing hyperbranched        compounds or dendrimers, difunctional or higher polyfunctional        (meth)acrylates such as trimethylolpropane tri(meth)acrylate, or        polyisocyanates containing (meth)acrylate groups;    -   additional crosslinking agents such as resins or compounds        containing anhydride groups, resins or compounds containing        epoxide groups, tris(alkoxycarbonylamino)triazines, resins or        compounds containing carbonate groups, blocked and/or unblocked        polyisocyanates, betahydroxyalkylamides, and compounds        containing on average at least two groups capable of        transesterification, examples being reaction products of malonic        diesters and polyisocyanates or of esters and partial esters of        polyhydric alcohols of malonic acid with monoisocyanates, as        described in European Patent EP 0 596 460 A1;    -   low-boiling and/or high-boiling organic solvents (“long        solvents”);    -   UV absorbers and/or other light stabilizers such as        benzotriazoles or oxalanilides or free-radical scavengers such        as HALS compounds;    -   photoinitiators such as those of the Norrish II type, whose        mechanism of action is based on an intramolecular variant of the        hydrogen abstraction reactions as occur diversely in the context        of photochemical reactions (reference may be made here by way of        example to Römpp Chemie Lexikon, 9th, expanded and revised        edition, Georg Thieme Verlag, Stuttgart, Vol. 4, 1991), or        cationic photoinitiators (reference may be made here by way of        example to Römpp Lexikon Lacke und Druckfarben, Georg Thieme        Verlag, Stuttgart, 1998, pages 444 to 446), especially        benzophenones, benzoins or benzoin ethers, or phosphine oxides;    -   thermally labile free-radical initiators such as organic        peroxides, organic azo compounds or C—C-cleaving initiators such        as dialkyl peroxides, peroxocarboxylic acids,        peroxodicarbonates, peroxide esters, hydroperoxides, ketone        peroxides, azo dinitriles, or benzpinacol silyl ethers;    -   crosslinking catalysts such as dibutyltin dilaurate, lithium        decanoate or zinc octoate or strong acids such as organic        sulfonic acids, which may have been blocked with amines;    -   devolatilizers, such as diazadicycloundecane;    -   slip additives;    -   polymerization inhibitors;    -   defoamers;    -   emulsifiers, especially nonionic emulsifiers such as alkoxylated        alkanols, polyols, phenols and alkylphenols, or anionic        emulsifiers such as alkali metal salts or ammonium salts of        alkanecarboxylic acids, alkanesulfonic acids, and sulfo acids of        alkoxylated alkanols, polyols, phenols and alkylphenols;    -   wetting agents such as siloxanes, fluorine compounds, carboxylic        monoesters, phosphoric esters, polyacrylic acids and their        copolymers, or polyurethanes;    -   adhesion promoters such as tricyclodecanedimethanol;    -   leveling agents;    -   film-forming auxiliaries such as cellulose derivatives;    -   transparent fillers based on silicon dioxide, aluminum oxide or        zirconium oxide; for further details, reference is made to Römpp        Lexikon Lacke und Druckfarben, Georg Thieme Verlag, Stuttgart,        1998, pages 250 to 252;    -   rheology control additives, such as those known from Patents WO        94/22968, EP 0 276 501 A1, EP 0 249 201 A1, and WO 97/12945;        crosslinked polymeric microparticles, as disclosed, for example,        in EP 0 008 127 A; inorganic phyllosilicates such as        aluminum-magnesium silicates, sodium-magnesium and        sodium-magnesium-fluorine-lithium phyllosilicates of the        montmorillonite type; silicas such as aerosils; or synthetic        polymers containing ionic and/or associative groups, such as        polyvinyl alcohol, poly(meth)acrylamide, poly(meth)acrylic acid,        polyvinylpyrrolidone, styrene-maleic anhydride or        ethylene-maleic anhydride copolymers and their derivatives, or        hydrophobically modified, ethoxylated urethanes or        polyacrylates;    -   flame retardants, and/or    -   flatting agents such as magnesium stearate.

Further examples of suitable additives are described in the textbook“Lackadditive” by Johan Bielemann, Wiley-VCH, Weinheim, N.Y., 1998.

The above-described additives may also be present in the adhesives andsealing compounds of the invention, provided they are suitable for thesepurposes, something which the skilled worker may readily determine onthe basis of his or her general knowledge of the art.

The preparation of the coating materials, adhesives, and sealingcompounds of the invention has no special features but instead takesplace in customary and known manner by mixing of the above-describedconstituents in suitable mixing equipment such as stirred vessels,dissolvers, stirred mills or extruders in accordance with the processessuitable for preparing the respective coating materials, adhesives, andsealing compounds of the invention.

The adhesives of the invention are used to produce the adhesive films ofthe invention on primed and unprimed substrates.

The sealing compounds of the invention are used to produce the seals ofthe invention on and/or in primed and unprimed substrates.

The coating materials of the invention are used in particular to producesingle-coat or multicoat clearcoats and/or multicoat color and/or effectsystems on primed and unprimed substrates. The coating materials of theinvention are found particularly advantageous in these utilities. Veryparticular advantages result in the case of their use to produceclearcoats, especially as part of the so-called wet-on-wet technique, inwhich a basecoat material, especially an aqueous basecoat material, isapplied to the primed or unprimed substrate and dried, but not cured,after which a clearcoat material of the invention, especially a powderslurry clearcoat of the invention, is applied to the basecoat film andthe resultant clearcoat film is cured together with the basecoat film,thermally and with actinic radiation.

Suitable substrates include all surfaces to be coated which areundamaged by curing of the films present thereon using a combination ofheat and actinic radiation.

Suitable substrates comprise metals, plastics, wood, ceramic, stone,textile, fiber composites, leather, glass, glass fibers, glass wool,rock wool, mineral- and resin-bound building materials, such asplasterboards and cement slabs or roof tiles, and assemblies of thesematerials.

Accordingly, the coatings, adhesive films or seals of the invention arealso suitable for applications outside of automotive OEM finishing andrefinishing. They are especially suitable for the coating, bondingand/or sealing of furniture, windows and doors, of interior and exteriorconstructions, and for industrial coating, including coil coating,container coating, and the impregnation or coating of electricalcomponents. In the context of industrial coating, they are suitable forthe coating, bonding and/or sealing of virtually all parts for privateor industrial use, such as radiators, domestic appliances, small metalparts such as nuts and bolts, wheel caps, rims, packaging, or electricalcomponents such as motor windings or transformer windings.

In the case of electrically conductive substrates it is possible to useprimers, which are produced in a customary and known manner fromelectrodeposition coating materials. Suitable for this purpose are bothanodic and cathodic electrodeposition coating materials, but especiallycathodics.

It is also possible to coat, bond or seal primed or unprimed plasticsparts made, for example, of ABS, AMMA, ASA, CA, CAB, EP, UF, CF, MF,MPF, PF, PAN, PA, PE, HDPE, LDPE, LLDPE, UHMWPE, PC, PC/PBT, PC/PA, PET,PMMA, PP, PS, SB, PUR, PVC, RF, SAN, PBT, PPE, POM, PUR-RIM, SMC, BMC,PP-EPDM and UP (abbreviations to DIN 7728P1). Unfunctionalized and/ornonpolar substrate surfaces may be subjected to a conventionalpretreatment prior to coating, such as with a plasma or by flaming, ormay be provided with a water-based primer.

The coating materials, adhesives, and sealing compounds of theinvention, especially the coating materials of the invention, may beapplied by all customary application methods, such as spraying, knifecoating, brushing, flow coating, dipping, impregnating, trickling, orrolling, for example. The substrate to be coated may itself be at rest,with the application device or unit being moved. Alternatively, thesubstrate to be coated, especially a coil, may be moved, with theapplication unit being at rest relative to the substrate or being movedappropriately.

Preference is given to the use of spray application methods, such ascompressed air spraying, airless spraying, high-speed rotation,electrostatic spray application (ESTA), alone or in conjunction with hotspray applications such as hot air spraying, for example. Applicationmay be carried out at temperatures of max. 70 to 80° C., so thatappropriate application viscosities are obtained without the briefthermal load entailing any alteration or damage to the coating materialand its overspray, which may be intended for reprocessing. For instance,hot spraying may be configured such that the coating material is heatedonly very briefly in the spray nozzle or a short way upstream of thespray nozzle.

The spray booth used for the application may be operated, for example,with an optionally temperature-controllable circulation system, which isoperated with an appropriate absorption medium for the overspray, anexample being the coating material itself.

Application is preferably made under illumination with visible lightwith a wavelength of more than 550 nm, or in the absence of light. Thisprevents material alteration or damage to the coating material of theinvention and the overspray.

In general, the surfacer film, topcoat film, basecoat film, andclearcoat film are applied in a wet-film thickness such that after thefilms have been cured they give coats having the coat thicknesses whichare advantageous and necessary for their functions. In the case of thesurfacer film this thickness is from 10 to 150, preferably from 15 to120, with particular preference from 20 to 100, and in particular from25 to 90 μm; in the case of the topcoat it is from 5 to 90, preferablyfrom 10 to 80, with particular preference from 15 to 60, and inparticular from 20 to 50 μm; in the case of the basecoat it is from 5 to50, preferably from 10 to 40, with particular preference from 12 to 30,and in particular from 15 to 25 μm; and in the case of the clearcoats itis from 10 to 100, preferably from 15 to 80, with particular preferencefrom 20 to 70, and in particular from 25 to 60 μm.

Curing may take place after a certain rest period. This period may havea duration of from 30 s to 2 h, preferably from 1 min to 1 h, and inparticular from 1 min to 30 min. The rest period serves, for example,for the leveling and devolatilization of the applied films or for theevaporation of volatile constituents such as solvent or water. The restperiod may be shortened and/or assisted by the application of elevatedtemperatures of up to 80° C., provided this does not entail any damageor alteration to the applied films, such as premature completecrosslinking.

In accordance with the invention, curing takes place with actinicradiation, in particular with UV radiation, and/or with electron beams.If desired, it may be conducted or supplemented with actinic radiationfrom other sources. In the case of electron beams, it is preferred tooperate under an inert gas atmosphere. This may be ensured, for example,by supplying carbon dioxide and/or nitrogen directly to the surface ofthe applied films.

In the case of UV radiation curing as well it is possible to operateunder inert gas, so as to prevent the formation of ozone.

Actinic radiation curing is carried out using the customary and knownradiation sources and optical auxiliary measures. Examples of suitableradiation sources are high-pressure or low-pressure mercury vapor lamps,with or without lead doping in order to open up a radiation window of upto 405 nm, or electron beam sources. The arrangement of these sources isknown in principle and may be adapted to the circumstances of theworkpiece and the process parameters. In the case of workpieces ofcomplex shape such as automobile bodies, those areas not accessible todirect radiation (shadow regions), such as cavities, folds and otherstructural undercuts, may be cured using point, small-area or all-roundemitters, in conjunction with an automatic movement device for theirradiation of cavities or edges.

The equipment and conditions for these curing methods are described, forexample, in R. Holmes, U.V. and E.B. Curing Formulations for PrintingInks, Coatings and Paints, SITA Technology, Academic Press, London,United Kingdom, 1984.

Curing here may take place in stages, i.e., by multiple exposure tolight or to actinic radiation. It may also take place alternatingly,i.e., by curing alternately with UV radiation and electron beams.

The thermal curing as well has no special features in terms of itsmethod but instead takes place in accordance with the customary andknown methods such as heating in a convection oven or irradiation withIR lamps. As with the actinic radiation curing, the thermal curing maytake place in stages. The thermal curing advantageously takes place at atemperature >90° C., preferably from 90 to 180° C., with particularpreference from 110 to 160° C., and in particular from 120 to 150° C.,for a time of from 1 min to 2 h, with particular preference from 2 minto 1 h, and in particular from 3 min to 30 min.

Thermal curing and actinic radiation curing may be used simultaneouslyor in alternation. If the two curing methods are used in alternation, itis possible, for example, to commence with heat curing and end withactinic radiation curing. In other cases it may prove advantageous tocommence and to end with actinic radiation curing. The skilled worker isable to determine the curing method most advantageous for the particularcase on the basis of his or her general knowledge in the art, possiblywith the aid of simple preliminary experiments.

The adhesive films and seals of the invention produced from thedual-cure adhesives and dual-cure sealing compounds of the inventionhave an outstanding bond strength and sealing capacity, even over longperiods, and even under extremely and/or rapidly changing climaticconditions.

The coatings of the invention produced from the coating materials of theinvention possess excellent leveling and have an outstanding overallvisual appearance. They are stable to weathering and do not yellow evenin a tropical climate. They can therefore be used in the interior andthe exterior sector.

The multicoat color and/or effect systems produced with the aid of thecoating process of the invention are of the utmost optical quality asregards color, effect, gloss, and DOI (distinctiveness of the reflectedimage), have a smooth, unstructured, hard, flexible, andscratch-resistant surface, are weathering-stable, chemical-resistant andetch-resistant, do not yellow, and show no cracking or delamination ofthe coats.

As a result, the primed and unprimed substrates of the invention,especially bodies of automobiles and commercial vehicles, industrialcomponents, including plastics parts, packaging, coils, and electricalcomponents, or furniture, which have been coated with at least onecoating of the invention, sealed with at least one seal of theinvention, and/or bonded with at least one adhesive of the invention,also exhibit special technical and economic advantages, in particular along service life, so making them particularly attractive to users.

EXAMPLES Preparation Example 1 The Preparation of an Allophanate fromHexamethylene Diisocyanate and 2-hydroxyethyl Acrylate

The allophanate was prepared as in German Patent DE-A-198 60 041,Experimental Section 1.1, Product No. 6. For this purpose, hexamethylenediisocyanate was mixed under nitrogen blanketing with 40 mol % (based onthe isocyanate) of 2-hydroxyethyl acrylate and the mixture was heated to80° C. Following the addition of 200 ppm by weight (based on theisocyanate) of N,N,N-trimethyl-N-(2-hydroxypropyl)-ammonium2-ethylhexanoate, the reaction mixture was heated slowly to 120° C. andheld at this reaction temperature. When the isocyanate content of thereaction mixture was 13.5% by weight, the reaction was stopped by adding250 ppm by weight (based on the isocyanate) of di(2-ethylhexyl)phosphate. The reaction mixture was then freed from unreactedhexamethylene diisocyanate in a thin-film evaporator at 135° C. and 2.5mbar. After distillation, the resultant allophanate had an isocyanatecontent of 13.5% by weight and a viscosity of 810 mPas at 23° C.

Example 1 The Preparation of the Inventive Polyurethane Dispersion 1

In a stirred vessel, 335 parts by weight of the allophanate ofPreparation Example 1 were reacted in the stated sequence with 30 partsby weight of hydroxypropyl carbamate, 50 parts by weight ofcyclohexanedimethanol, 8 parts by weight of hydroxy acetic acid and, forblocking of the excess isocyanate groups, with 12 parts by weight ofn-butanol. The resultant polyurethane had an acid number of 8.5 mgKOH/g. It was neutralized with 11 parts by weight of triethylamine. Theneutralized polyurethane was dispersed in water to give a solids contentof 43% by weight (1 h/130° C.).

Example 2 The Preparation of the Inventive Polyurethane Dispersion 2

Example 1 was repeated except that 376 parts by weight of a commercialisocyanurate of hexamethylene diisocyanate (Desmodur® N 3300 from BayerAG) were used instead of the allophanate of Preparation Example 1.

Examples 3 to 6 The Preparation of the Inventive Clearcoats 3 to 6

The inventive clearcoats 3 to 6 were prepared by mixing the constituentslisted in Table 1 in a dissolver (rotary speed: 3000 rpm; disk diameter:3 cm; duration: 30 min). In the case of Examples 5 and 6, the aminoresin and the catalyst were mixed beforehand and then stirred as apremix into the dispersion.

TABLE 1 The material composition of the inventive clearcoats of Examples3 to 6 Parts by weight: Example Constituent 3 4 5 6 Polyurethanedispersion 1 100 — 100 — Polyurethane dispersion 2 — 100 — 100 Byk ®348^(a)) 0.4 0.4 0.4 0.4 Irgacure ® 184^(b)) 2.7 2.7 2.7 2.7 Cymel ®325^(c)) — — 3 3 catalyst^(d)) — — 0.06 0.06 ^(a))Polyether-modifiedpolydimethylsiloxane from Byk ^(b))1-Hydroxycyclohexyl phenyl ketone,50% strength in Texanol/isopropanol 1:2 (Ciba Additives) ^(c))Commercialamino resin from Cytec ^(d))Amine-blocked benzenesulfonic acid (Nacure ®2500 from King Industries)

The clearcoats of Examples 3 and 4 are thermally self-crosslinkingclearcoats.

The clearcoats of Examples 5 and 6 are thermally externally crosslinkingclearcoats.

Examples 7 to 10 The Preparation of the Inventive Multicoat ColorSystems 7 to 10

Clearcoat 3 was used for Example 7, clearcoat 4 for Example 8, clearcoat5 for Example 9, and clearcoat 6 for Example 10.

A commercial aqueous surfacer (Ecoprime® R130 from BASF Coatings AG),first of all, was applied using a gravity-feed gun to steel panelscoated (electrodeposition coating with a coat thickness of 18-22 μm)cathodically with a commercial electrodeposition coating material(Cathoguard® 500 from BASF Coatings AG), and the panels were baked. Thisgave a surfacer coating having a coat thickness of from 35 to 40 μm.Subsequently, in the same way, a black aqueous basecoat (Basislacknachtschwarz FV96-9400 from BASF Coatings AG) was applied to thesurfacer and dried at 80° C. for 10 minutes. After the panels hadcooled, in each case in each case [sic] one film of clearcoats 3 to 6was applied in a wet-film thickness of 150 μm, using a gravity-feed gun,and each film was flashed off at room temperature for 10 minutes anddried at room temperature for 2 minutes (wet-on-wet technique).

Subsequently, the test panels were exposed to UV radiation with a doseof 1500 mJ/cm². They were subsequently baked at 150° C. for 30 minutes(dual cure). This gave a basecoat having a dry thickness of 16 μm and aclearcoat having a dry thickness of 45 μm.

The scratch resistance was determined in accordance with the sand test.For this purpose, the film surfaces were stressed with sand (20 g ofquartz silver sand, 1.5-2.0 mm). The sand was placed in beakers (cut offplane at the bottom) which were fastened securely to the test panels ofExamples 7 to 10. By means of a motor drive, the test panels with thebeakers and the sand were set in shaking movement. The movement of theloose sand caused damage to the film surfaces (100 double strokes in 20s). Following sand exposure, the test areas were cleaned of the abradedmaterial, wiped down carefully under a jet of cold water, and then driedusing compressed air. The gloss to DIN 67530 was measured before andafter damage (measurement direction perpendicular to the direction ofscratching). Table 2 gives an overview of the results obtained.

TABLE 2 Scratch resistance of the inv ntive multicoat systems 7 to 10 bythe sand test Examples: Gloss to DIN 67530 7 8 9 10 Initial: 81.6 82.681 83.4 After damage: 27.7 43.9 60.6 76.7 2 h at 40° C.: 27.4 30.4 64.676.7 2 h at 60° C.: 29.8 40.3 64.6 78.1

The sand test underscored the high scratch resistance of the inventivemulticoat systems of Examples 9 and 10. The multicoat systems producedfrom the thermally self-crosslinking clearcoats 3 and 4 do not fullyattain the high level.

Examples 11 to 14 The Production of the Inventive Clearcoats 11 to 14

Clearcoat 3 was used for Example 11, clearcoat 4 for Example 12,clearcoat 5 for Example 13, and clearcoat 6 for Example 14.

For Examples 11 to 14, the clearcoats 3 to 6 were applied to test panelsas normally used to measure the micropenetration hardness. The curingconditions employed were the same as those for Examples 7 to 10. Thedry-film thickness of the inventive clearcoats 11 to 14 was 45 μm.

The results summarized in Table 3 demonstrate the good mechanicalstability of the clearcoats 11 and 12 produced from the thermallyself-crosslinking clearcoats 3 and 4. The level was significantlyincreased further by the use of crosslinking agents (cf. Examples 13 and14).

TABLE 3 Micropenetration hardness and creep at 25.6 mN of the clearcoats11 to 14 Parameter: Examples I II III IV V VI 11 126.4 10.2 2.77 41.5 20−36 12 137.8 14.4 2.66 37.8 18.4 −35.6 13 161.9 11.7 2.45 47.3 11.8−21.4 14 163.4 1.7 2.43 49.2 8.2 −23.2 I Universal hardness at 25.6 mN(N/mm²) II Standard deviation of the universal hardness III Averagepenetration depth (μm) IV Relative elastic resilience (%) V Creep at25.6 mN (%) VI Creep at 0.4 mN (%)

Examples 15 to 18 The Production of the Inventive Clearcoats 15 to 18

The clearcoat 3 was used for Example 15, clearcoat 4 for Example 16,clearcoat 5 for Example 17, and clearcoat 6 for Example 18.

For Examples 15 to 18, the clearcoats 3 to 6 were applied to steelpanels with white basecoats. The curing conditions employed were thesame as those for Examples 7 to 10. The dry-film thickness of theinventive clearcoats 11 to 14 was 45 μm.

Table 4 gives an overview of the tendency of the clearcoats 11 to 14 toyellow. The yellowing resistance was found by calorimetric determinationof the yellow value by the Cielab method. The results demonstrate thehigh yellowing resistance.

TABLE 4 The yellowing resistance of the inventive clearcoats inaccordance with determination of the yellow value by the Cielab methodInitial: After one week: Examples L* a* b* L* a* b* 15 89.0 −2.2 2.688.4 −2.1 2.5 16 88.8 −2.1 4.8 88.7 −2.3 3.6 17 87.9 −2.3 3.6 87.8 −2.33.6 18 88.7 −2.0 3.4 88.7 −2.0 3.2

1. A dual cure aqueous dispersion comprising at least one polyurethanepolymer, the polyurethane polymer comprising on average: (i) at leastone primary carbamate group; (ii) more than five groups that are atleast one of a methacrylate group, an acrylate group, or a mixturethereof; and (iii) at least one dispersive ionic functional group;wherein the dual cure aqueous dispersion cures via the application ofboth heat and actinic radiation and further wherein the at least oneprimary carbamate group is separated from all of the groups of (ii) byat least 8 chemical bonds prior to curing; and wherein the polyurethanepolymer is prepared by a process comprising reacting: (A) at least onealiphatic polyisocyanate having an isocyanate functionality of from 2.0to 6.0; (B) at least one compound comprising at least oneisocyanate-reactive functional group and at least one of a methacrylategroup, an acrylate group, or a mixture thereof; (C) at least one lowmolecular weight aliphatic compound comprising a plurality ofisocyanate-reactive functional groups; (D) at least one compoundcomprising at least one isocyanate-reactive functional group and atleast one dispersive potentially ionic, functional group; (E) at leastone neutralizing agent for the dispersive potentially ionic functionalgroups of the compound (D); and (F) at least one compound comprising: I.at least one of: i. a primary carbamate group; and ii. at least onecyclic ethylene carbonate group; and II. at least oneisocyanate-reactive group; and (G) optionally, at least one compoundcomprising an isocyanate-reactive functional group, other than thecompounds (B) to (F), wherein said groups (i), (ii), and (iii) in saidpolyurethane polymer correspond to groups in the reactant compounds (F),(B), and (D), respectively, and wherein the isocyanate-reactive groupsin compounds (B), (C), (D), and (F) form urethane linkages in thepolyurethane polymer.
 2. The aqueous dispersion of claim 1, wherein theat least one dispersive ionic functional group is present in an amountto give, based on the solids of the dispersion, an acid number or aminenumber of from 3.0 to 100 mg KOH/g.
 3. The aqueous dispersion of claim1, wherein the at least one dispersive ionic functional group is ananionic group.
 4. The aqueous dispersion of claim 1, wherein the degreeof neutralization of the at least one dispersive ionic functional groupis at least 60 mol %.
 5. The aqueous dispersion of claim 4, wherein thedegree of neutralization is at least 95 mol %.
 6. The aqueous dispersionof claim 1, wherein the polymer comprises on average at least twocarbamate groups.
 7. The aqueous dispersion of claim 1, wherein thepolymer further comprises (iv) at least one isocyanate-reactivefunctional group.
 8. The aqueous dispersion of claim 7, wherein the atleast one isocyanate-reactive functional group is at least one of athiol group, a hydroxyl group, a primary amino group, and a secondaryamino group.
 9. The aqueous dispersion of claim 1, wherein the at leastone dispersive anionic functional group is at least one of a carboxylategroup, a sulfonate group, and a phosphonate group.
 10. The aqueousdispersion of claim 1, wherein the at least one aliphatic polyisocyanatecomprises an aliphatic polyisocyanate comprising at least one of anisocyanurate group, a biuret group, an allophanate group, animinooxadiazinedione group, a urethane group, a urea group, acarbodiimide group, and a uretdione group.
 11. The aqueous dispersion ofclaim 10, wherein the at least one aliphatic polyisocyanate comprises ahexamethylene diisocyanate that comprises at least one of an allophanategroup and an isocyanurate group.
 12. The aqueous dispersion of claim 1,wherein the at least one compound (B) at least one of a hydroxyalkylester of (meth)acrylic acid, a hydroxycycloalkyl ester of (meth)acrylicacid, a reaction product of a cyclic ester and a hydroxyalkyl ester of(meth)acrylic acid, or a reaction product of a cyclic ester and ahydroxycycloalkyl ester of (meth)acrylic acid.
 13. The aqueousdispersion of claim 1, wherein the at least one low molecular massaliphatic compound comprising a plurality of isocyanate-reactivefunctional groups comprises at least one of a polyol, a polyamine,polyol amine, and polyamino alcohol.
 14. The aqueous dispersion of claim1, wherein the at least one compound comprising at least oneisocyanate-reactive functional group and at least one dispersivepotentially ionic, functional group is at least one of amercapto-carboxylic acid, a mercaptophosphonic acid, a mercaptosulfonicacid, a hydroxy-carboxylic acid, a hydroxyphosphonic acid, ahydroxysulfonic acid, an aminocarboxylic acid, an aminophosphonic acid,an aminosulfonic acid, an iminocarboxylic acid, an iminophosphonic acid,and an iminosulfonic acid.
 15. The aqueous dispersion of claim 1,wherein the at least one neutralizing agent comprises an organic amine.16. The aqueous dispersion of claim 1, wherein the compounds (F)comprise a hydroxyalkyl carbamate.
 17. The aqueous dispersion of claim1, wherein the compound (G) comprises at least one of an alcohol and amonoamine.
 18. A method comprising applying the aqueous dispersion ofclaim 1 to at least one of on and in a substrate and forming one of anat least one coating, an adhesive, and a sealant.
 19. The method ofclaim 18, wherein the at least one coating is one of a single-coatclearcoat, a multicoat clearcoat, and a coating system that is at leastone of color and effect.
 20. The method of claim 18, wherein the atleast one coating is at least one of a surfacer, a solid-color topcoat,a basecoat, and a clearcoat.
 21. A composition comprising at least onedispersion of claim 1, wherein the composition is one of a coatingmaterial, an adhesive, and a sealing compound.
 22. The composition ofclaim 21 further comprising at least one crosslinking agent comprisingat least one amino resin.
 23. The dual cure aqueous dispersion of claim1 wherein the heat and actinic radiation are used in alternation.
 24. Adual cure aqueous dispersion comprising at least one polyurethanepolymer, the polyurethane polymer comprising on average: (i) at leastone primary carbamate group; (ii) more than five groups that are atleast one of a methacrylate group, an acrylate group, or a mixturethereof; and (iii) at least one dispersive ionic functional group;wherein the dual cure aqueous dispersion cures via the application ofboth heat and actinic radiation and further wherein the at least oneprimary carbamate group is separated from all of the groups of (ii) byat least 8 chemical bonds prior to curing; and wherein the polyurethanepolymer is prepared by a process comprising reacting: (A) at least onealiphatic polyisocyanate (A) having an isocyanate functionality of from2.0 to 6.0 and comprising at least one of an isocyanurate group, abiuret group, an allophanate group, an iminooxadiazinedione group, aurethane group, a urea group, a carbodiimide group, and a uretdionegroup; (B) at least one compound (B) comprising at least oneisocyanate-reactive functional group and at least one of a methacrylategroup, an acrylate group, or a mixture thereof, wherein compound (B)comprises at least one of a hydroxyalkyl ester of methacrylic acid oracrylic acid, a hydroxycycloalkyl ester of methacrylic acid or acrylicacid, a reaction product of a cyclic ester and a hydroxyalkyl ester ofmethacrylic acid or acrylic acid, or a reaction product of a cyclicester and a hydroxycycloalkyl ester of methacrylic acid or acrylic acid,wherein compound (B) is reacted in a first process step with a molarexcess of compound (A) to give an adduct containing free isocyanategroups and bonds that may be activated with actinic radiation; (C) atleast one low molecular weight aliphatic compound (C) comprising aplurality of isocyanate-reactive functional groups, which compound (C)is at least one of a polyol, a polyamine, and an amino alcohol; (D) atleast one compound (D) comprising at least one isocyanate-reactivefunctional group and at least one dispersive potentially ionic,functional group, which compound (D) is at least one of amercaptocarboxylic acid, a mercaptophosphonic acid, a mercaptosulfonicacid, a hydroxy-carboxylic acid, a hydroxyphosphonic acid, ahydroxysulfonic acid, an aminocarboxylic acid, an aminophosphonic acid,an aminosulfonic acid, an iminocarboxylic acid, an iminophosphonic acid,and an iminosulfonic acid; (E) at least one neutralizing agent (E) forthe dispersive potentially ionic functional groups of the compound (D);and (F) at least one compound (F) comprising: I. at least one of: i. aprimary carbamate group; and ii. at least one cyclic ethylene carbonategroup; and II. at least one isocyanate-reactive group; and (G)optionally, at least one compound (G) comprising an isocyanate-reactivefunctional group, other than the compounds (B) to (F), wherein saidgroups (i), (ii), and (iii) in said polyurethane polymer correspond togroups in the reactant compounds (F), (B), and (D), respectively, andwherein the isocyanate-reactive groups in compounds (B), (C), (D), and(F) form urethane linkages in the polyurethane polymer, with the provisothat the polyurethane polymer does not comprise silicon-carbon bonds.25. The aqueous dispersion of claim 24 further comprising an aminoresin.
 26. A dual cure aqueous dispersion comprising at least onepolyurethane polymer, the polyurethane polymer comprising on average thefollowing groups: (i) at least one primary carbamate group; (ii) morethan five groups that are at least one of a methacrylate group, anacrylate group, or a mixture thereof; and (iii) at least one dispersiveionic functional group; wherein the dual cure aqueous dispersion curesvia the application of both heat and actinic radiation and furtherwherein the at least one primary carbamate group is separated from allof the groups of (ii) by at least 8 chemical bonds prior to curing;wherein the polyurethane polymer is prepared by a process comprisingreacting the following reactant compounds: (A) at least one aliphaticpolyisocyanate having an isocyanate functionality of from 2.0 to 6.0;(B) at least one compound comprising at least one isocyanate-reactivefunctional group and at least one of a methacrylate group, an acrylategroup, or a mixture thereof; (C) at least one low molecular weightaliphatic compound comprising a plurality of isocyanate-reactivefunctional groups; (D) at least one compound comprising at least oneisocyanate-reactive functional group and at least one dispersivepotentially ionic, functional group; (E) at least one neutralizing agentfor the dispersive potentially ionic functional groups of the compound(D); and (F) at least one compound comprising: I. at least one of: i. acarbamate group that is at least one of primary and secondary; and ii.at least one cyclic ethylene carbonate group; and II. at least oneisocyanate-reactive group; and (G) optionally, at least one compoundcomprising an isocyanate-reactive functional group, other than thecompounds (B) to (F); and wherein said groups (i), (ii), and (iii) insaid polyurethane polymer correspond to groups in the reactant compounds(F), (B), and (D), respectively, wherein the isocyanate-reactive groupsin compounds (B), (C), (D), and (F) form urethane linkages in thepolyurethane polymer, and wherein compounds (B), (D), and (F) react withisocyanate functionality consisting of the isocyanate functionality ofcompound (A).
 27. The aqueous dispersion of claim 26, wherein thecoating formed from the aqueous dispersion when cured is scratchresistant to the extent that after scratch testing with sand (100 doublestrokes in 20 seconds), at least 74.8% of the initial gloss measured toDIN 67530 is retained.
 28. The aqueous dispersion of claim 26, whereinthe coating formed from the aqueous dispersion when cured has amicropenetration hardness at 25.6 millinewtons of at least 161.9 Newtonsper square millimeter and a penetration depth of no greater than 2.43micrometers.
 29. The aqueous dispersion of claim 26, wherein the coatingformed from the aqueous dispersion when cured has a creep at 25.6millinewtons of no greater than 11.8%.